This application claims the priority of German Application 10 2004 058 606.3, filed Dec. 3, 2004, the disclosure of which is expressly incorporated by reference herein.
This invention is concerned with a process for testing the tightness of a container. Additionally, the invention provides for a process for sealing a container after a test of its tightness has been made, as well as a device for sealing the container.
The lack of tightness of fuel tanks and other containers in aircraft is a problem with far reaching effects on flight safety and operational safety on the ground. This problem also affects work safety and environmental protection. If aircraft fuel tanks are lacking in tightness, substantial repair costs can result, and the operational readiness of an aircraft fleet could be impaired. During a delivery of a new or overhauled aircraft to a customer, all systems are given a final testing. Tightnesses of the tank installations are also tested. During the operation of the aircraft on the ground, as well as during air operations, leaks may occur over the aircraft life-cycle, typically more than 25 years. The leaks may be the result of mechanical damage of the tank walls due to improper handling of the aircraft or due to unplanned stresses caused by flight operations such as overloads or vibrations. In military aircraft especially, such leaks may occur when the aircraft is being fired upon.
It is in the interest of an airline operator to restore flight worthiness of the aircraft at as little expense in time and personnel as possible without having the aircraft spend time in the repair hangar of the manufacturer. Especially in integral tanks, that is to say tanks which are fitted in their spatial design to the external contour of the aircraft and/or to the internal contour of the aircraft, the tank inner walls have multiple joint locations at which leakages can occur, even though the state of the art of sealing technology is very high both with respect to manufacture and testing quality.
In spite of all the measures taken, leaks that must be located and sealed can spring up in the tank walls during operation of an aircraft.
It is one object this invention to provide a process for testing the tightnesses of containers which can be carried out without a great expense even when the containers have complex internal and/or external contours, such as, for example, in the case of integral aircraft tanks, and to permit rapid determination of leak locations. Furthermore, it must be possible to seal leaks quickly and without great cost.
Testing for leakage of a container according to the invention includes separating a first fluid in an interior space of the container from a second fluid surrounding the container, producing a negative pressure in the interior space, testing interior surfaces of container walls for traces of second fluid penetration, and localizing any points of entry of the second fluid.
According to the invention, a partial vacuum is created in the tank and subsequently tested to determine whether a fluid has penetrated the internal space of the container. This makes it possible to locate in a simple way the exact entry point of the fluid entering the inner space of the container. This reversal of the principle, known as such, of creating high pressure in the interior space of a container and observing at which point fluid exits the container, avoids disadvantages of this known solution, since the fluid escaping from the container frequently is not visible at its point of exit but rather at some distance from it.
The localization of the entry point can also be observed through a window provided in the container, and it can be observed, from the outside, where the second fluid enters the interior space of the container. Nevertheless, it is especially advantageous when a probe is or several probes are brought into the interior space of the container. Such probes can be designed so as to be stationary within the internal container space or movable along the container internal wall.
Advantageous additional improvements are additionally provided.
After completion of the process of testing the containers for leakage, that is to say, after the localization of the entry point, a sealing compound can be applied with the help of a probe from the inside of the container at the point of leakage. This probe can be either independent of the camera or a combined probe which, in addition to the camera and, as the case may be, a gas supply, can also include at least one suitable repair tool such as, for example, an injector or an extruder for the sealing compound.
A device according to the invention for testing for container leakage and for repair of leaks allows for a fast repair immediately after identification of a leakage point.